Google has announced a new quantum computing chip with 72 quantum bits, or qubits, the basic units of information in a quantum processor. Called “Bristlecone”, the company believes this chip could lead to a major breakthrough known as “quantum supremacy”— an achievement when a quantum processor can be operated with low enough error, enabling it to outperform a classical supercomputer on a well-defined computer science problem.
Google contends its Bristlecone chip demoes 1% error rates for readout, 0.1% for single-qubit gates, and 0.6% for two-qubit gates.
According to Google researchers, “the new superconducting system is developed to provide its researchers with a testbed for research into system error rates and scalability of the company’s qubit technology, as well as applications in quantum simulation, optimization, and machine learning. Its ultimate goal is to build a quantum computer that can be used to solve real-world problems.”
“Our strategy is to explore near-term applications using systems that are forward compatible to a large-scale universal error-corrected quantum computer. In order for a quantum processor to be able to run algorithms beyond the scope of classical simulations, it requires not only a large number of qubits. Crucially, the processor must also have low error rates on readout and logical operations, such as single and two-qubit gates.” commented Julian Kelly, Research Scientist, Quantum AI Lab.
Google’s new Bristlecone chip uses 72 qubits compared to just nine qubits in its previous 9-qubit linear quantum computer which demoed impressively low error rates for readout (1%), single-qubit gates (0.1%), and two-qubit gates (0.6%).
The device uses the same scheme for coupling, control, and readout. But instead of using a linear array design, it is scaled to a square array of 72 qubits.
The company said that it is looking to achieve similar error rates they were able to achieve on the 9-qubit hardware:
“We are cautiously optimistic that quantum supremacy can be achieved with Bristlecone, and feel that learning to build and operate devices at this level of performance is an exciting challenge! We look forward to sharing the results and allowing collaborators to run experiments in the future”, the company explained.
Google has also developed new benchmarking tools specifically for measuring the performance of Bristlecone.